Conventionally, vehicles running with the power supplied from wires are known. The power required for such a vehicle to run (running power) differs depending on environments, such as slopes of rails on which the vehicle runs. For this reason, the capacity and power consumption of a substation supplying the power to wires are determined based on a variation of the voltage caused by the running power.
Additionally, when such a vehicle brakes and thereby causes the regenerative power to be generated, the regenerative power is fed to the wires to prevent a regenerative failure. The regenerative power fed to the wires is collected by the substation. For this reason, an interval at which substations are to be installed is determined based on a variation of the voltage caused by the regenerative power.
In order to reduce costs for a traffic system by decreasing the number of substations to be installed, suppression of the peaks of the running power and the regenerative power (peak cut) has been considered. As a method of cutting the peaks of the running power and the regenerative power, there is a method in which a secondary battery is mounted on a vehicle to absorb the regenerative power and supplement the running power.
In order to adequately cut the peak of the power, it is necessary to adequately manage a charging rate of the secondary battery.
Patent Document 1 discloses a method of performing a charge so that a charging rate varies within an adequate range of the charging rate, thereby preventing a secondary battery mounted on a wire-less vehicle from deteriorating.
Patent Document 2 discloses a method of controlling a charging rate of a secondary battery mounted on a wire-less vehicle.